Removing leather from leather press



June '26, 1962 2 Sheets-Sheet 1 Poem L. GRIFFIN IN V EN TOR.

R. L. GRIFFIN 3,040,554 REMOVING LEATHER FROM LEATHER PRESS Filed Feb. 18, 1959 e 1962 R. L. GRIFFIN 3,

REMOVING LEATHER FROM LEATHER PRESS Filed Feb. 18, 1959 2 Sheets-Sheet 2 Poss? L. GmFF I N INVENTOR.

J lti'o rney ite Stats tent Patented June 26, 1962 ice This invention relates in general to automatic means for intermittently withdrawing sheet material a predetermined distance from a machine operating upon the material. More specifically, the present invention is concerned with a novel means for drawing sheet material, such as leather, from a reciprocating press in successive steps coordinated with the press cycle.

It is the usual practice to press sides of leather between two flat, horizontally disposed platens that are reciprocable between closed and opened positions. Normally about four successive pressing operations are required to. finish the entire length of a side of leather. Thus it has been necessary for the machine operators to carefully insert and advance the leather by hand between each pressing cycle. In the past, each press has required one operator to feed and a second operator to pull the leather from the press. This practice,has been uneconomical from both the standpoint of use of available manpower and utilization of the machine.

I am aware of certain attempts to facilitate the operation of apparatus for pressing leather. Most notable have been the devices whereby leather is carried between the platents by an endless conveyor. In one instance leather is carried through the press upon an endless conveyor belt, whereby both the leather and the belt are pressed. In another embodiment the leather is connected to crossbars suspended between endless chains extending alongside the press. In both of these embodiments cumbersome machinery hinders direct access to the press which may become necessary in case of malfunction. Further, the endless conveyor type arrangement necessarily interferes to a certain degree with the elfective and rapid operation of the press. Other embodiments include those where relatively small pieces of leather are carried upon a horizontally movable platen, or where the material to be pressed is in the form of a long, continuous web which may be wound on a spindle at the exit side of the press. Neither of the latter types of apparatus are readily adaptable to pressing individual sides of leather.

Therefore, it is a primary object of myinvention to provide an improved method and apparatus for auto matically and intermittently moving a side of leather through a reciprocating press between successive pressing cycles.

Another object is to provide an improved method and apparatus for drawing leather through a press whereby only a single operator will be required to attend the operation of the equipment. A further object is to provide an improvement in conveying means cooperating with the vertically movable platens to draw the leather therebetween only when the platens are moved apart.

Anadditional object is to provide an improved gr'ipping means in cooperation with, an endless conveyor to withdraw the leather when the press is open, whereby the conveyor will move the leather from the press.

My invention, as applied to a press having at least one vertically reciprocating platen,. comprises material engaging means located adjacent the platens, a conveyor extending from the press beyond the engaging means, and power means connected to operate the material engaging means and conveyor in coordination with the separation of the press platens. The engaging means grips and withdraws material extending from the press only during the interval that the platens are separated. Thus it may be seen that the basic advantage of the invention is the automatic removal of the material from the press with a consequent saving in manpower.

Further objects and advantages of my invention will become apparent from the following description taken in conjunction with the drawings wherein:

FIGURE 1 is a perspective view of the apparatus of my invention;

FIGURE 2 is a partial side elevation View with part of the frame removed for clarity;

FIGURE 3 is a schematic "elevation of the apparatus showing the relative positions when the press is open;

FIGURE 4 is a schematic side view showing the position of the apparatus when the press is closed; and

FIGURE 5 is a perspective view of the power means with simplified wiring and pneumatic circuits shown schematically, to illustrate the controlfeatures of the apparatus.

The method of my invention comprises first inserting a side of leather into a leather press; then engaging the leather and partially withdrawing the pressed end thereof only during the interval that the press is opened. The leather is removed at a rate to withdraw a portion no greater than the length of the portion of the side of leather that has been pressed. Subsequently, as the press is again closed, withdrawal of the leather is stopped and the side is released so that the side of leather will be free to realign itself as it extends from the press. The sequence is then repeated until the entire side is removed from the press.

The present apparatus may be positioned to automatically advance leather to an unloading or stacking apparatus such as that disclosed in my earlier Patent No. 2,855,089, issued October 7, 1958, the disclosure of which is included herein by reference. Furthermore, the present apparatus may be used in conjunction with the aforementioned leather stacking apparatus and my computing device described'in Patent No. 2,837,198, issued June 3, 1958, and Patent No. 2,987,162, issued June 6, 1961, the disclosures of whic are also included herein by reference.

Referring to the drawings, the apparatus is associated with a leather press generally llll of the type manufactured by the Sheridan Company of New York, one embodiment of which is described in Patent No. 2,043,246 to T. B. l-lawkes. Press It) includes a stationary upper platen l2 and a reciprocable lower platen 14. The lower platen 14 is reciprocated by means of a cam driven system of toggles generally 15. In certain finishing operations the upper platen may be heated by any well-known means such as electrical heating elements or steam conduits.

Adjacent the discharge side of the press 10 are a feed roll 16, an idler roll 18 directly above and parallel to the feed roll, and a pulley iii of a conveyor generally 22 comprising a plurality of endless belts 23. The rolls and pulley are rotatably mounted in a pairof end frames 24 'so that the rolls 16 and 18 are located between the press 10 and conveyor 22. Preferably feed roll 16 is positioned with the uppermost portion of its periphery approximately at the level of the lower platen 14 when the press 10 is in the fully opened positions. The conveyor pulley 20 is located slightly below feed roll 16 so that leather passing from the latter will fall onto the belts 2.3.

Feed roll 16 is mounted on an axle 26 which is suitably journaled in the end frames 24. The idler roll 18, having a discontinuous surface formed annular rims 27 spaced along an axle 28, is journaled in a pair of pillow blocks 30. The pillow blocks are movable vertlcally within slots in the end frames 24. Roll 18 is normally urged away from roll 16 by means of a of a plurality of pair of compression springs 32 connected between the pillow blocks 30 and end frames 24. However, the rims 27 of idler roll 18 may "be forced into contact with feed roll 16 by pneumatic cylinders 34 secured to each end frame directly above pillow blocks 30. Reciprocable piston rods 36, extending from the pneumatic cylinders 34, are fastened to theupper surface of the pillow blocks 30. The piston rods 36 force the pillow blocks 30, and thereby idler roll 18, downwardly when air under pressure is introduced to the cylinders 34.

The conveyor 22 and feed. roll 16 may be operated by a convenient power means, generally 37, actuated intermittently upon the opening of the press 10. I have devised the equipment shown in FIGURE especially for this purpose. As may be seen in FIGURE 2 both the feed roll 16 and the conveyor pulley are driven by a chain 38 trained about their respective sprockets 39, 40. Chain 38 in turn passes about the output of a gear reducer 41. The size of sprockets 39 and 40 is governed by the output speed of the gear reducer and the diameters of the feed roll 16 and pulley 20, respectively. Sprockets 39 and 40 are selected to provide equal surface speeds for the roll 16 and conveyor 22. The latter speed is regulated to withdraw the leather a desired amount during the interval that the platens 12, 14 are separated. In practice, the Sheridan type press operates at about 13 cycles per minute; and the leather must be withdrawn in increments of about 22 inches.

As may be best seen in FIGURE 5, one end of a shaft 42 is connected to the input of gear reducer 41 and rotatably supported by a bearing 43. A driven clutch plate 44 is keyed to the free end of shaft 42 so that rotary motion applied to the plate will be transmitted through the gear reducer 41 to roll 16 and pulley 20.

A parallel driving disc 45, normally spaced a short distance from the plate 44, is mounted to freely rotate on the end of a rod 46 extending from a pneumatic cylinder 47 and reciprocably supported by a bearing 48. Disc has a shoulder concentric to its periphery on the face toward clutch plate 44 and is adapted to support a drive belt 49. The belt 49 is trained between disc 45 and a drive pulley on an electric motor 50. The motor is located so that the drive belt 49 extends from disc 45 at a slight angle away from clutch plate 44, to normally urge disc 45 away from the plate. be readily understood, when compressed air is introduced into cylinder 47 rod 46 and disc 45 will be forced toward plate 44 until a side of the drive belt 49 is pressed thereagainst. Thus so long as the air pressure is maintained in cylinder 47 power will be supplied from motor 50 to the gear reducer 41 and thence to conveyor 22 and feed roll 16.

Since the roll 16 is required to withdraw material from the press 10 in uniform increments it is desirable to pro- Vide some type of braking device to quickly stop the motion in gear reducer 41 when the clutch plate 44 and disc 45 are disengaged. For this purpose a pivotable brake band 51 is provided along shaft 42. Band 51 is normally held against shaft 42 to prevent its rotation by means of a tension spring 52. However, a pneumatic lifter 53 is provided to pivot the band 51 away from the shaft when compressed air is directed to the cylinder 47.

Operation. of the feed roll 16 and conveyor 22 is controlled by -a timing assembly connected to axle 26, As may be seen in FIGURE 2, a timing cam 55 is driven by gear chain 56 from a gear 57 on axle 26, so as to rotate once for every 22 inches of linear travel of feed roll 16. The cam 55 trips a switch 58 mounted on the end frame 24. Switch 58 forms part of an electrical circuit (to be later described) and. is normally closed. When the switch is momentarily opened compressed air will be diverted from cylinder 47 thus allowing the clutch plate 44 and disc 45 to disengage.

A similar but normally open switch 59 is mounted on a side of press 16 where it will be tripped once per cycle However, as will by a part of the press power train. This may be conveniently done, as shown in FIGURE 1, by fastening a trip rod 61 on the press flywheel 62 so as to close the switch 59 momentarily when the platens 12, 14 are at least partially separated. It will become clear that the momentary closing of switch 59 will cause engagement of the plate and disc of the power means, generally 37.

Referring to FIGURE 5, it may be seen that switches 58 and 59 are connected in parallel between one terminal of a v.a.c. power supply and a double switch relay generally 63, A wire connects switch 59 directly to one end'of a coil 64 in relay 63. Switch 58 is connected through one of the relay switches 65 to the same end of coil 64. The other end of the coil 64 is connected to the opposite terminal of the power supply. The second switch 66 of the relay 63 is connected in series between a solenoid 67 and the power supply.

Thus, when switch 59 is closed by trip rod 61, the coil 64 will-be energized and switches 65 and 66 will be closed thereby. Switch 65, when closed, completes a secondary holding circuit for coil 64 through the normally closed switch 58. Therefore, when switch 59 is subsequently released to the normally open position the coil will remain energized, and switches 65 and 66 will be maintained closed, until cam 55 momentarily opens switch 58 to break the holding circuit.

During the period that coil 64 is energized, and switch 66 is closed, the circuit to solenoid 67 will be maintained. The solenoid operates a spring loaded valve 68 to connect a pipe 69 to a source of compressed air (not shown) and a main 72 supplying a plurality of tubes 73, 74, 75 to cylinder 47, lifter 53, and cylinder 34, respectively. When the circuit to solenoid 67 is broken valve 68 will return to its normal position connecting main 72 and an exhaust line 70 which empties into the atmosphere.

In operation, as the lower platen 14 of press 10/ moves downwardly, trip rod 61 on flywheel 62 closes the normally open switch 59 for a short interval. As noted, this energizes the coil 64 of relay 63 to close switches 65 and 66 thus completing the electrical circuit to the solenoid 67 which in turn moves valve 68 to connect the compressed air to main 72. Air under pressure will be directed to cylinder 47 advancing disc 45 into engagement with the clutch plate 44 to deliver power to the conveyor 22 and feed roll 16. At the same time brake 51 will be lifted from the shaft 42 by the pneumatic lifter 53. Also compressed air will reach cylinder 34 causing the idler roll 18 to be pushed against the action of spring 32 into contact with feed roll 16.

Leather extending from the press 16 between the rolls 16 and 18 will then be engaged thereby and withdrawn at an established rate of speed until the proper length has been removed and cam 55 opens switch 58. In practice, switch 59 quickly returns to the normally open position and the action of cam 55 will break the electrical circuit to the relay coil 64 which in turn breaks the circuit to solenoid 67. The valve 68 will then return to its normal position, exhausting the pneumatically actuated elements to disengage the clutch plate 44 and disc 45; brake shaft 42; and release idler roll 18. The timing of cam 55 is such that switch 58 is opened when the proper length of leather has been withdrawn. This occurs at about the time platen 14 moves upwardly and just before the press closes. The force of compression springs 32 will urge pillow blocks 39 upwardly and lift the idler roll 18 from contact with the leather and feed roll 16.

This sequence of operation will repeat automatically even after the entire side of leather has passed through the press 10. At that point it is only necessary for a single operator to manually insert another side of leather in the press. Following the first cycle on a new side of leather, the operator must then, as the platens open, manually insert the leading edge of the leather between rolls 16 and 18 after which the operation is entirely automatic.

obvious modifications will occur to a 7 operating only Movement of the rolls 16 and 18 to the open position, as the press closes, has been found to be advantageous in that the leather is released from confinement and is subject only to internal forces. Thus, if by chance the leather has started to wrinkle or twist, it will be free to straighten out before the press is completely closed. Additionally the discontinuous surface of idler roll 18, comprising the rims 2,7, materially alleviates the tendency for longitudinal Wrinkles to form when the leather is subjected to a pulling force. Such a tendency is pronounced where the leather, for some reason, might be untimely gripped by the platens or by some object on the input side of the press. Furthermore, should wrinkles appear, the discontinuous surf-ace otf idler roll 18 allows such wrinkles to pass between adjacent areas of contact with roll 16 without being permanently ironed into the leather.

The foregoing detailed description is only for clearness of understanding and for the purpose of complying with 35 USC 112, and I do not desire to be limited to the exact details of construction shown and described for person skilled in the art.

I claim:

1. An improved apparatus for withdrawing sheet mate rial from a press reciprocating between open and closed positions comprising: a conveying means for transporting the sheet material from the discharge end of the press; sheet engaging means positioned between the press and said conveying means adapted to grip and withdraw material extending from said press and advance it to said conveying means, said engaging means normally being inoperative to grip said material; actuating means connected to said engaging means to cause said engaging means to grip said material only during the interval that the press remains open; and power means to cause said engaging means to withdraw said material a distance not exceeding the length of material normally enclosed in said press during said interval.

2. An improved apparatus for withdrawing sheet material sfrom a press reciprocating between open and closed positions comprising: a conveyor adjacent the discharge end of the press; a pair of cooperating rolls for engaging and withdrawing the sheet material positioned intermediate said conveyor and said press; bias means connected to at least one of said rolls to normally urge said rolls apart;

actuating means operable to move said rolls together a whereby to grip the material therebetween, said actuating means being constrained to operate only when said press moves to the open position; and power means torotate said conveyor and at least one of said rolls whereby the surfaces thereof will move a distance not exceeding the length of material normally enclosed in said press during the period said press is closed, said power means operating only during the interval said press remains open.

3. An improved apparatus for withdrawing sheet material from a press reciprocating between open and closed positions comprising: a conveyor adjacent the discharge end of the press; a pair of cooperating rolls for engaging and withdrawing the sheet material positioned intermediate said conveyor and said press; springsoperatively connected to at least one of said rolls to normally urge said rolls apart; actuating means operable to move said rolls together whereby to grip the material therebetween, said actuating means being constrained to operate only when said press moves to the open position; and power means to rotate said conveyor and at least one of said rolls whereby the surfaces thereof will move a distance not exceeding the length of material normally enclosed in said press during the period said press is closed, said power means during the interval that the press remains open.

4. An improved apparatus for withdrawing sheet material from a press reciprocating between open and closed positions comprising: a conveyor adjacent the discharge end of the press; a pair of cooperating rolls for engaging and Withdrawing the sheet material positioned intermediate said conveyor and said press; bias means operatively connected to at least one of said rolls to normally urge said rolls apart; pneumatic cylinders operatively connected to at lease one of said rolls to move said rolls together whereby to grip the material therebetween, said cylinders being constrained to operate only when said press moves to the open position; and power means to rotate said conveyor and at least one of said rolls whereby the surfaces thereof will move a distance not exceeding the length of material normally enclosed in said press during the period said press is closed, said power means operating only during the interval said press remains open.

5. An improved apparatus for withdrawing sheet material from a press reciprocating between open and closed positions comprising: a conveyor adjacent the discharge end of the press; a pair of cooperating rolls for engaging and withdrawing the sheet material positioned intermediate said conveyor and said press; springs operatively connected to at least one of said rolls to normally urge said rolls apart; pneumatic cylinders operatively connected to said one roll to move said rolls together whereby to grip the material therebetween, said cylinders being constrained to operate only when said press moves to the open position; and means to rotate said conveyor and at least one of said rolls an amount whereby the surfaces terial from a press having platens reciprocating between 7 open and closed positions comprising: a frame adjacent the discharge end of the press; a conveyor mounted on said frame and extending from said press, said conveyor being positioned at a level below at least one of the press platens when in the open position; a feed roll journaled within said frame and located parallel to and intermediate the press and said conveyor; disengageable power means to drive said conveyor and said feed roll at substantially the same linear speed in a direction away from said press, said speed being suflicient to move the material a distance not greater than the length normally pressed when the press is closed during the interval that the press is open; a pair of pillow bearings positioned above the ends of said feed roll, said pillow bearings being mounted within vertical slots in said frame so as to be movable vertically with respect to said feed roll; an idler roll rotatably supported between said pillow bearings parallel to said feed roll; springs connected to said pillow bearings and said frame normally urging said idler roll upwardly away from said feed roll; pneumatic means connected to said pillow bearings operable to force said idler roll downwardly into engagement with said feed roll whereby to grip material extending from said press; and

control means connected to cause said power means and said pneumatic means to operate only when the press is 

